CN116260035B - Laser system and optical fiber gain medium protection device and method - Google Patents
Laser system and optical fiber gain medium protection device and method Download PDFInfo
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- CN116260035B CN116260035B CN202310323038.1A CN202310323038A CN116260035B CN 116260035 B CN116260035 B CN 116260035B CN 202310323038 A CN202310323038 A CN 202310323038A CN 116260035 B CN116260035 B CN 116260035B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/0912—Electronics or drivers for the pump source, i.e. details of drivers or circuitry specific for laser pumping
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Abstract
The invention discloses a laser system and an optical fiber gain medium protection device and method, wherein the optical fiber gain medium protection device comprises a photoelectric conversion circuit, a comparison circuit, a sampling circuit, a control module and a power supply control circuit, wherein the photoelectric conversion circuit is used for receiving seed optical signals and converting the optical signals into analog signals to be respectively input into the comparison circuit and the sampling circuit, the input end of the sampling circuit is connected with the output end of the photoelectric conversion circuit, the output end of the sampling circuit is connected with the first input end of the control module, the input end of the comparison circuit is connected with the output end of the photoelectric conversion circuit, the output end of the comparison circuit is connected with the second input end of the control module, the output end of the control module is connected with the input end of the power supply control circuit, and the output end of the power supply control circuit is connected with a pumping source. The optical fiber gain medium protection device can effectively ensure the safety of the photonic crystal fiber and reduce the failure rate of a laser.
Description
Technical Field
The invention belongs to the field of laser control, and particularly relates to a laser system, and an optical fiber gain medium protection device and method.
Background
Femtosecond lasers have many incomparable advantages, so that the femtosecond lasers play an increasing role in the fields of measurement, microelectronics, microelectromechanical systems, chemistry, biology, medicine, military and the like. With the increasing maturity of the femtosecond laser technology, the femtosecond laser has an indisputable position in the fields of nuclear physics, femtosecond pulse spectroscopy, ultra-high speed optical communication and the like.
There are four main categories of femtosecond laser gain media: organic dye, titanium doped sapphire, li: SAF, solid materials such as doped forsterite, multi-quantum well materials and SiO2 doped with rare earth elements, and the doped photonic crystal fiber which takes the SiO2 doped with rare earth elements as a gain medium is represented, and the photonic crystal fiber has the obvious characteristics of flexible design, high refractive index contrast and the like compared with the common fiber because of the unique structural characteristics of the photonic crystal fiber. Particularly, the double-cladding photonic crystal fiber combining the photonic crystal fiber and the cladding pumping technology has larger mode field area and larger numerical aperture of an inner cladding, so that nonlinear effect and efficiency reduction caused by high power and amplified spontaneous radiation are avoided, the coupling efficiency of pumping light is improved, and conditions are provided for further improvement of a high-beam quality and high-power fiber laser.
However, photonic crystal fibers are expensive, such as a large-mode-area fiber "rod" can be as expensive as tens of thousands of euros. And the laser output power of a single optical fiber cannot be infinitely improved, and the laser output power is limited by various factors of the laser output power, such as thermal effects, nonlinear effects (such as stimulated Raman scattering and stimulated Brillouin scattering), damage to the end face of the optical fiber and the like, and especially damage to the end face of the optical fiber can directly influence the output power of the optical fiber laser.
When both the seed light and the pump light are coupled into the photonic crystal fiber, if the seed light coupled into the photonic crystal fiber does not reach a set value for a period of time, the pump light coupled into the photonic crystal fiber can damage the photonic crystal fiber.
Disclosure of Invention
In order to solve the problem that the photonic crystal fiber is vulnerable, the invention provides a laser system, an optical fiber gain medium protection device and a method.
The technical scheme of the invention is realized as follows: the invention discloses an optical fiber gain medium protection device which comprises a photoelectric conversion circuit, a control module, a power supply control circuit and a comparison circuit or/and sampling circuit, wherein the photoelectric conversion circuit is used for receiving seed optical signals and converting the optical signals into analog signals, the input end of the sampling circuit is connected with the output end of the photoelectric conversion circuit, the output end of the sampling circuit is connected with the first input end of the control module, the input end of the comparison circuit is connected with the output end of the photoelectric conversion circuit, the output end of the comparison circuit is connected with the second input end of the control module, the output end of the control module is connected with the input end of the power supply control circuit, and the output end of the power supply control circuit is connected with a pumping source.
Further, the photoelectric conversion circuit is used for receiving an optical signal separated from an input seed optical signal of the photonic crystal fiber.
Further, the comparison circuit is used for receiving the analog signal output by the photoelectric conversion circuit in real time, comparing the analog signal with a preset comparison value, outputting a first level to the control module when the analog signal is larger than the preset comparison value, and outputting a second level to the control module when the analog signal is smaller than the preset comparison value;
when the control module finds that the input level jumps from the first level to the second level, the control module outputs a control signal to the power supply control circuit to control the power supply control circuit to cut off the power supply and the current of the pumping source.
Further, the sampling circuit is used for sampling the analog signal output by the photoelectric conversion circuit in real time and transmitting the sampled value to the control module; the control module is used for receiving the sampling value, comparing the sampling value with a preset alarm range value, and outputting a control signal to the power supply control circuit when the sampling value exceeds the preset alarm range value so as to control the power supply control circuit to cut off the power supply and the current of the pumping source.
Further, the photoelectric conversion circuit comprises a photoelectric tube D1 and an operational amplifier U1, wherein the positive electrode of the photoelectric tube D1 is connected with one end of a resistor R1 and one end of a resistor R2, the other end of the resistor R1 is grounded, the other end of the resistor R2 is connected with the positive electrode input end of the operational amplifier U1, the negative electrode of the photoelectric tube D1 is respectively connected with one end of a resistor R3 and one end of a capacitor C1, the other end of the capacitor C1 is grounded, the other end of the resistor R3 is connected with one end of an inductor L1, the other end of the inductor L1 is connected with a first voltage, the negative electrode input end of the operational amplifier U1 is connected with the output end of the operational amplifier U1, and the output end of the operational amplifier U1 is used for outputting a required signal.
Further, the photoelectric conversion circuit further includes an operational amplifier U2, an anode input end of the operational amplifier U2 is configured to receive a signal output by the operational amplifier U1, a cathode input end of the operational amplifier U2 is respectively connected with one end of a resistor R5 and a first fixed end of a potentiometer RW1, another end of the resistor R5 is grounded, a second fixed end of the potentiometer RW1 and a sliding end thereof are connected with an output end of the operational amplifier U2, and an output end of the operational amplifier U2 is configured to output a required signal.
Further, the photoelectric conversion circuit further comprises a filtering and current limiting circuit, and the filtering and current limiting circuit is arranged at the output end of the operational amplifier U1.
Further, the filtering and current limiting circuit is located between the output end of the operational amplifier U1 and the positive input end of the operational amplifier U2.
The filtering and current limiting circuit comprises a resistor R4 and a capacitor C4, one end of the resistor R4 is connected with the output end of the operational amplifier U1, the other end of the resistor R4 is connected with one end of the capacitor C4, and the other end of the capacitor C4 is grounded.
Further, the control module adopts an FPGA.
Further, the comparison circuit comprises an operational amplifier U3, the positive input end of the operational amplifier U3 is connected with one end of a resistor R6, the other end of the resistor R6 is connected with the output end of the photoelectric conversion circuit, the negative input end of the operational amplifier U3 is respectively connected with one end of a capacitor C8 and the sliding end of a potentiometer RW2, the other end of the capacitor C8 is grounded, the first fixed end of the potentiometer RW2 is grounded, the second fixed end of the potentiometer RW2 is connected with a second voltage, the output end of the operational amplifier U3 is connected with one end of a resistor R7, the other end of the resistor R7 is connected with the second voltage, and the output end of the operational amplifier U3 is the output end of the comparison circuit.
Further, the power supply control circuit includes an operational amplifier U5, an optocoupler U4, a MOS transistor Q1 and a MOS transistor Q2, the positive input terminal of the operational amplifier U5 is connected with one end of a resistor R10 and the drain of the MOS transistor Q1, the other end of the resistor R10 is connected with a voltage VSET, the source of the MOS transistor Q1 is grounded, the gate of the MOS transistor Q1 is connected with a first output terminal EN of a control module and one end of a resistor R11, the other end of the resistor R11 is grounded, the negative input terminal of the operational amplifier U5 is connected with one end of a resistor R12, the other end of the resistor R12 is connected with one end of a resistor R17 and the source of the MOS transistor Q2, the other end of the resistor R17 is grounded, the drain of the MOS transistor Q2 is connected with a first pin of an interface for connecting a pumping source, the gate of the MOS transistor Q2 is connected with one end of a resistor R16, the other end of the resistor R16 is connected with one end of a resistor R14, one end of a resistor R15 is grounded, the other end of the resistor R14 is connected with the output terminal of the control module, the other end of the resistor R14 is connected with the output terminal of the operational amplifier U5, the other end of the output terminal of the resistor R4 is connected with the second end of the output terminal of the optocoupler U9, the second end of the output terminal of the diode is connected with the second output terminal of the second diode 2, and the output terminal of the second diode is connected with the second output terminal of the output diode 2 is connected with the second output terminal of the output diode 2.
The invention discloses a laser system, which comprises a seed light source, an optical splitter, a pumping source, a photonic crystal fiber and the optical fiber gain medium protection device;
the seed light source is used for outputting seed light;
the optical splitter is used for receiving the seed light and dividing the seed light into two paths, wherein one path of light is transmitted to the photonic crystal fiber through the seed optical coupling system, and the other path of light is transmitted to the fiber gain medium protection device;
the optical fiber gain medium protection device is used for receiving the seed optical signal, carrying out anomaly detection and controlling the working state of the pumping source;
the pump source is used for outputting pump light and is coupled into the photonic crystal fiber through the pump optical coupling system. The invention discloses a protection method for an optical fiber gain medium of a femtosecond laser, which comprises the following steps:
s1) dividing part of input signal light of the photonic crystal fiber according to a set proportion and inputting the part of the input signal light as an input optical signal into a photoelectric conversion circuit;
s2) the photoelectric conversion circuit receives an input optical signal, converts the optical signal into an electric signal and inputs the electric signal to the comparison circuit or/and the sampling circuit respectively;
s3) sampling the analog signal output by the photoelectric conversion circuit in real time by the sampling circuit, transmitting the sampling value to the control module, receiving the sampling value by the control module, comparing the sampling value with a preset alarm range value, and executing the step S4 when the sampling value exceeds the preset alarm range value;
the comparison circuit receives the analog signal output by the photoelectric conversion circuit in real time, compares the analog signal with a preset comparison value, outputs a comparison result to the control module, and executes the step S4 when the control module judges that the comparison result is abnormal;
s4) the control module outputs a control signal to the power supply control circuit to control the power supply control circuit to cut off the power supply and the current of the pumping source.
Further, the comparison circuit receives the analog signal output by the photoelectric conversion circuit in real time, compares the analog signal with a preset comparison value, outputs a first level to the control module when the analog signal is larger than the preset comparison value, and outputs a second level to the control module when the analog signal is smaller than the preset comparison value;
when the control module finds that the input level jumps from the first level to the second level, step S4 is performed.
The invention has at least the following beneficial effects: the invention designs an optical fiber gain medium protection device based on a femtosecond pulse optical fiber laser, which is used for monitoring an input seed light signal of an optical fiber crystal in real time, cutting off power supply and current of a pumping source when the seed light is abnormal, protecting the optical fiber crystal, and reducing the fault rate of the laser.
The optical fiber gain medium protection device has the advantages of short single detection period, high instantaneity, sensitive response, quick action, total time from detection of abnormality to completion of turn-off action of less than 500 microseconds, no current overshoot after turn-off and strong protection capability.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a functional block diagram of a laser system provided by an embodiment of the present invention;
FIG. 2 is a flowchart of a method for protecting an optical fiber gain medium based on a femtosecond pulse optical fiber laser according to an embodiment of the present invention;
FIG. 3 is a schematic block diagram of an optical fiber gain medium protection device based on a femtosecond pulse fiber laser according to an embodiment of the present invention;
fig. 4 is a circuit diagram of a photoelectric conversion circuit of an optical fiber gain medium protection device based on a femtosecond pulse optical fiber laser according to an embodiment of the present invention;
FIG. 5 is a circuit diagram of a comparison circuit of a fiber gain medium protection device based on a femtosecond pulse fiber laser according to an embodiment of the present invention;
fig. 6 is a circuit diagram of a power supply control circuit of an optical fiber gain medium protection device based on a femtosecond pulse optical fiber laser according to an embodiment of the present invention;
fig. 7 is a circuit diagram of a sampling circuit of an optical fiber gain medium protection device based on a femtosecond pulse optical fiber laser according to an embodiment of the present invention;
fig. 8 is a partial circuit diagram of an FPGA of a fiber gain medium protection device based on a femtosecond pulse fiber laser according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second" may include one or more such features, either explicitly or implicitly; in the description of the present invention, unless otherwise indicated, the meaning of "a plurality", "a number" or "a plurality" is two or more.
Example 1
Referring to fig. 1 to 8, the embodiment of the invention discloses an optical fiber gain medium protection device based on a femtosecond pulse optical fiber laser, which comprises a photoelectric conversion circuit, a power supply circuit, a control module, a power supply control circuit, a comparison circuit and a sampling circuit, wherein the power supply circuit is used for supplying power to the whole device, the photoelectric conversion circuit is used for receiving a seed optical signal and converting the optical signal into an analog signal to be respectively input into the comparison circuit and the sampling circuit, the input end of the sampling circuit is connected with the output end of the photoelectric conversion circuit, the output end of the sampling circuit is connected with the first input end of the control module, the input end of the comparison circuit is connected with the output end of the photoelectric conversion circuit, the output end of the comparison circuit is connected with the second input end of the control module, the output end of the control module is connected with the input end of the power supply control circuit, and the output end of the power supply control circuit is connected with a pumping source.
Further, the photoelectric conversion circuit is used for receiving a seed optical signal separated from an input seed optical signal of the photonic crystal fiber.
Further, the comparison circuit is used for receiving the analog signal output by the photoelectric conversion circuit in real time, comparing the analog signal with a preset comparison value, outputting a first level to the control module when the analog signal is greater than or equal to the preset comparison value, and outputting a second level to the control module when the analog signal is less than the preset comparison value;
when the control module finds that the input level jumps from the first level to the second level, the control module outputs a control signal to the power supply control circuit to control the power supply control circuit to cut off the power supply and the current of the pumping source.
Further, the sampling circuit is used for sampling the analog signal output by the photoelectric conversion circuit in real time and transmitting the sampled value to the control module; the control module is used for receiving the sampling value, comparing the sampling value with a preset alarm range value, and outputting a control signal to the power supply control circuit when the sampling value exceeds the preset alarm range value so as to control the power supply control circuit to cut off the power supply and the current of the pumping source.
The control module of the protection device, such as an FPGA, is used for comparing the sampled value of the software with a preset alarm value, and outputting a level representing normal or abnormal to the main control module of the control system, wherein the preset alarm value is directly transmitted to the control module of the protection device, such as the FPGA, by the main control module of the control system, so that comparison and judgment can be completed relatively quickly.
The preset comparison value is a voltage signal and is an analog value; the software presets the alarm lower limit to be a digital quantity after ADC conversion, and because the software sampling is also subjected to some processing to filter sampling errors, some correction processing is carried out on the actual sampled value, for example, a correction measure is as follows: the actual sample value is multiplied by k (k can be found experimentally). The preset alarm value and the preset comparison value are related to the beam splitting optical power of the seed when the laser works normally. The seed source is higher than the set upper limit and can lead to output power reduction, the seed source is lower than the set lower limit and can lead to the damage of the photonic crystal fiber, the setting of the software preset alarm range needs to ensure that the photonic crystal fiber cannot be damaged, and the output power is not affected. The preset comparison value needs to be set to ensure that the photonic crystal fiber is not damaged.
Furthermore, in order to ensure rapid sampling and real-time responsiveness, the invention can adopt an FPGA as a control module. Of course, the control module of the present invention is not limited to FPGA, but may be MCU, etc. The advantage of high parallelism of the FPGA can ensure that the sampling value after mean value processing is reported to the main control module in real time while high-speed sampling is performed; similarly, the invention employs an ADC sampling rate greater than 10MSPS.
The FPGA receives a preset alarm range value downloaded by a main control module of the control system through a design serial port module RXD pin, and an ADC sampling value obtained in an SPI communication mode is sent to the main control module of the control system through the TXD pin.
The sampling circuit may or may not be integrated within the control module.
The sampling circuit samples the analog quantity in real time and transmits the sampling value to the control module, the control module compares the sampling value with a preset software alarm range value, and meanwhile, the control module reports the sampling value to the control system to be used as a data display and backup record.
Further, the photoelectric conversion circuit includes a photoelectric cell D1, an operational amplifier U1 and an operational amplifier U2, the positive electrode of the photoelectric cell D1 is connected to one end of a resistor R1 and one end of a resistor R2, the other end of the resistor R1 is grounded, the other end of the resistor R2 is connected to the positive electrode input end of the operational amplifier U1, the negative electrode of the photoelectric cell D1 is respectively connected to one end of a resistor R3 and one end of a capacitor C1, the other end of the capacitor C1 is grounded, the other end of the resistor R3 is connected to one end of an inductor L1, the other end of the inductor L1 is connected to a first voltage, the negative electrode input end of the operational amplifier U1 is connected to the output end of the operational amplifier U1, the output end of the operational amplifier U1 is connected to one end of a resistor R4, the other end of the resistor R4 is grounded to one end of a capacitor C4 and the positive electrode input end of the operational amplifier U2, the negative electrode input end of the operational amplifier U2 is respectively connected to one end of a resistor R5 and the first fixed end of a potentiometer RW1, the other end of the resistor R5 is grounded, the second fixed end of the potentiometer RW1 and the second fixed end of the output end of the operational amplifier is connected to the output end of the operational amplifier U2.
As shown in fig. 4, when a pulse optical signal is input to a phototube with a specified wavelength, the phototube is judged to be on according to the working principle that the phototube is on when the phototube has optical input and is off when no optical input is provided, the voltage drop Vop at the end R1 when the phototube is on can be obtained by properly adjusting the resistance value of R1, and the required corresponding voltage value Vop2 of light intensity can be obtained after the primary operational amplifier and the secondary operational amplifier, namely the input light intensity ein=vop2 and vop2=0 when no optical input is provided.
The first-stage operational amplifier (operational amplifier U1) is used for converting a frequency signal into a continuous signal, when the signal output by the first-stage operational amplifier is weaker, the second-stage operational amplifier (operational amplifier U2) is required to amplify the signal, and the gain multiple of the 2-stage operational amplifier can be adjusted to amplify the amplitude of the output signal.
Further, the comparator is adopted by the comparison circuit, the homodromous input end of the comparator is connected with the output end of the photoelectric conversion circuit, and the reverse input end V-of the comparator is connected with the reference circuit (the reference circuit is used for outputting a reference voltage, namely a preset comparison value, and the reference voltage, namely the preset comparison value, is adjustable).
The photoelectric conversion circuit inputs the voltage corresponding to the processed optical signal into the homodromous input end V+ of the comparator, the input voltage of the reverse input end V-pre-connected sliding resistor of the comparator is 0, and the magnitude of the input voltage of the V-end can be adjusted by adjusting the sliding resistance value. According to the working principle of the comparator, if light is continuously input into the photoelectric tube during normal operation, the voltage of the V+ terminal is kept unchanged, and the voltage of the V-terminal is regulated to be lower than the voltage value of the V+ terminal, so that the output voltage of the comparator is high level; when the input light of the photoelectric tube is weakened or disappears, V- > V+ is generated at the moment, and the output voltage of the comparator is low.
The output level of the comparator is directly input into the FPGA for processing, and when the FPGA finds that the input level jumps from high level to low level, a protection action is generated. Meanwhile, the hardware comparison circuit can filter out the circuit noise influence accompanied by software sampling.
Further, the comparison circuit comprises an operational amplifier U3, the positive input end of the operational amplifier U3 is connected with one end of a resistor R6, the other end of the resistor R6 is connected with the output end of the photoelectric conversion circuit, the negative input end of the operational amplifier U3 is respectively connected with one end of a capacitor C8 and the sliding end of a potentiometer RW2, the other end of the capacitor C8 is grounded, the first fixed end of the potentiometer RW2 is grounded, the second fixed end of the potentiometer RW2 is connected with a second voltage, the output end of the operational amplifier U3 is connected with one end of a resistor R7, the other end of the resistor R7 is connected with the second voltage, and the output end of the operational amplifier U3 is the output end of the comparison circuit.
Further, the power supply control circuit includes an operational amplifier U5, an optocoupler U4, a MOS transistor Q1 and a MOS transistor Q2, the positive input terminal of the operational amplifier U5 is connected with one end of a resistor R10 and the drain of the MOS transistor Q1, the other end of the resistor R10 is connected with a voltage VSET, the source of the MOS transistor Q1 is grounded, the gate of the MOS transistor Q1 is connected with a first output terminal EN of a control module and one end of a resistor R11, the other end of the resistor R11 is grounded, the negative input terminal of the operational amplifier U5 is connected with one end of a resistor R12, the other end of the resistor R12 is connected with one end of a resistor R17 and the source of the MOS transistor Q2, the other end of the resistor R17 is grounded, the drain of the MOS transistor Q2 is connected with a first pin of an interface for connecting a pumping source, the gate of the MOS transistor Q2 is connected with one end of a resistor R16, the other end of the resistor R16 is connected with one end of a resistor R14, one end of a resistor R15 is grounded, the other end of the resistor R14 is connected with the output terminal of the control module, the other end of the resistor R14 is connected with the output terminal of the operational amplifier U5, the other end of the output terminal of the resistor R4 is connected with the second end of the output terminal of the optocoupler U9, the second end of the output terminal of the diode is connected with the second output terminal of the second diode 2, and the output terminal of the second diode is connected with the second output terminal of the output diode 2 is connected with the second output terminal of the output diode 2.
The voltage VSET is output by a DAC (digital-to-analog converter) controlled by a main control module or a main control chip of the control system, and when the FPGA of the protection device detects that the seed light source is abnormal, a signal is sent to the main control module of the control system, and the main control module of the control system controls the DAC to output 0.
Referring to fig. 6, pins 1 and 2 of the interface for connecting the pump source are respectively used for connecting the anode and the cathode of the pump source.
In the real-time detection process, when the FPGA detects that the software sampling or hardware comparison circuit does not meet the preset requirement, the states of the IO_switch pin and the EN pin are immediately changed, and the current of the pumping LD is cut off in a mode of cutting off power supply and giving current, so that the photonic crystal fiber is protected.
Example two
The embodiment of the invention discloses an optical fiber gain medium protection device based on a femtosecond pulse optical fiber laser, which comprises a photoelectric conversion circuit, a power supply circuit, a control module, a power supply control circuit and a comparison circuit, wherein a sampling circuit is not arranged in the protection device, and the control module controls the power supply control circuit according to a comparison result output by the comparison circuit. Other corresponding technical features of the present embodiment are the same as those of the first embodiment.
Example III
The embodiment of the invention discloses an optical fiber gain medium protection device based on a femtosecond pulse optical fiber laser, which comprises a photoelectric conversion circuit, a power supply circuit, a control module, a power supply control circuit and a sampling circuit, wherein a comparison circuit is not arranged in the protection device, the control module compares a sampling value of the sampling circuit with a preset alarm range value, and the power supply control circuit is controlled according to a software comparison result. Other corresponding technical features of the present embodiment are the same as those of the first embodiment.
Example IV
Referring to fig. 1, the invention discloses a laser system, which comprises a seed light source, an optical splitter, a pump source, a photonic crystal fiber and an optical fiber gain medium protection device as described in embodiment one, embodiment two or embodiment three;
the seed light source is used for outputting seed light;
the optical splitter is used for receiving the seed light and dividing the seed light into two paths, wherein one path of light is transmitted to the photonic crystal fiber through the seed optical coupling system, and the other path of light is transmitted to the fiber gain medium protection device;
the optical fiber gain medium protection device is used for receiving the seed optical signal, performing abnormality detection (such as judging whether the preset requirement is met or not) and controlling the working state of the pumping source;
the pump source is used for outputting pump light and is coupled into the photonic crystal fiber through the pump optical coupling system.
The laser system also comprises a control system, the control system comprises a main control module, the main control module of the control system is communicated with the control module of the optical fiber gain medium protection device, and the control module of the optical fiber gain medium protection device is used for reporting the sampling value to the main control module of the control system in real time and receiving a preset alarm range value downloaded by the main control module of the control system.
Example five
Referring to fig. 2, the embodiment of the invention discloses a method for protecting an optical fiber gain medium of a femtosecond laser, which comprises the following steps:
s1) dividing part of input signal light of the photonic crystal fiber according to a set proportion and inputting the part of the input signal light as an input optical signal into a photoelectric conversion circuit;
s2) the photoelectric conversion circuit receives an input optical signal, converts the optical signal into an electric signal and inputs the electric signal to the comparison circuit or/and the sampling circuit respectively;
s3) performing a first abnormality detection step including: the sampling circuit samples the analog signal output by the photoelectric conversion circuit in real time and transmits the sampled value to the control module, the control module receives the sampled value and compares the sampled value with a preset alarm range value, when the sampled value exceeds the preset alarm range value, the step S4) is executed, otherwise, the first abnormality detection step is continuously executed;
performing a second anomaly detection step comprising: the comparison circuit receives the analog signal output by the photoelectric conversion circuit in real time, compares the analog signal with a preset comparison value (such as a preset hardware alarm voltage), outputs a comparison result to the control module, and executes the step S4 when the control module judges that the comparison result is abnormal, otherwise, continues to execute the second abnormality detection step;
s4) the control module outputs a control signal to the power supply control circuit to control the power supply control circuit to cut off the power supply and the current of the pumping source, for example, the power supply and the current are rapidly cut off to protect the photonic crystal fiber.
Further, the comparison circuit receives the analog signal output by the photoelectric conversion circuit in real time, compares the analog signal with a preset comparison value, outputs a first level (such as a high level) to the control module when the analog signal is greater than or equal to the preset comparison value, and outputs a second level (such as a low level) to the control module when the analog signal is less than the preset comparison value; when the control module finds that the input level jumps from the first level to the second level, step S4 is performed.
Further, S1) specifically includes: the input signal light of the photonic crystal fiber is split according to an equal proportion and is input into a photoelectric conversion circuit as an input signal.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (8)
1. An optical fiber gain medium protection device is characterized in that: the device comprises a photoelectric conversion circuit, a control module, a power supply control circuit and a comparison circuit or/and sampling circuit, wherein the photoelectric conversion circuit is used for receiving a seed optical signal and converting the optical signal into an analog signal, the input end of the sampling circuit is connected with the output end of the photoelectric conversion circuit, the output end of the sampling circuit is connected with the first input end of the control module, the input end of the comparison circuit is connected with the output end of the photoelectric conversion circuit, the output end of the comparison circuit is connected with the second input end of the control module, the output end of the control module is connected with the input end of the power supply control circuit, and the output end of the power supply control circuit is connected with a pumping source;
the comparison circuit is used for receiving the analog signal output by the photoelectric conversion circuit in real time, comparing the analog signal with a preset comparison value, outputting a first level to the control module when the analog signal is larger than the preset comparison value, and outputting a second level to the control module when the analog signal is smaller than the preset comparison value;
when the control module finds that the input level jumps from the first level to the second level, the control module outputs a control signal to the power supply control circuit to control the power supply control circuit to cut off the power supply and the current of the pumping source;
the sampling circuit is used for sampling the analog signals output by the photoelectric conversion circuit in real time and transmitting the sampled values to the control module; the control module is used for receiving the sampling value, comparing the sampling value with a preset alarm range value, and outputting a control signal to the power supply control circuit when the sampling value exceeds the preset alarm range value so as to control the power supply control circuit to cut off the power supply and the current of the pumping source;
the power supply control circuit comprises an operational amplifier U5, an optocoupler U4, a MOS tube Q1 and a MOS tube Q2, wherein the positive electrode input end of the operational amplifier U5 is respectively connected with one end of a resistor R10 and the drain electrode of the MOS tube Q1, the other end of the resistor R10 is connected with a voltage VSET, the source electrode of the MOS tube Q1 is grounded, the grid electrode of the MOS tube Q1 is respectively connected with a first output end EN of a control module and one end of a resistor R11, the other end of the resistor R11 is grounded, the negative electrode input end of the operational amplifier U5 is connected with one end of a resistor R12, the other end of the resistor R12 is respectively connected with one end of a resistor R17 and the source electrode of the MOS tube Q2, the other end of the resistor R17 is grounded, the drain electrode of the MOS tube Q2 is connected with a first pin of an interface for connecting a pumping source, the grid of MOS pipe Q2 is connected with one end of resistance R16, the other end of resistance R16 is connected with one end of resistance R14, one end of resistance R15 respectively, the other end ground connection of resistance R15, the other end of resistance R14 is connected with the output of fortune amplifier U5, the first input of opto-coupler U4 is connected with one end of resistance R9, the second voltage is connected to the other end of resistance R9, the second input of opto-coupler U4 is connected with one end of resistance R8 and the second output IO_switch of control module, the second voltage is connected to the other end of resistance R8, the first output of opto-coupler U4 is connected with the positive pole of diode D2, the third voltage is connected to the negative pole of diode D2, the second output of opto-coupler U4 is connected with the second pin of the interface that is used for connecting the pumping source.
2. The optical fiber gain medium protection device of claim 1, wherein: the photoelectric conversion circuit comprises a photoelectric tube D1 and an operational amplifier U1, wherein the positive electrode of the photoelectric tube D1 is connected with one end of a resistor R1 and one end of a resistor R2, the other end of the resistor R1 is grounded, the other end of the resistor R2 is connected with the positive electrode input end of the operational amplifier U1, the negative electrode of the photoelectric tube D1 is respectively connected with one end of a resistor R3 and one end of a capacitor C1, the other end of the capacitor C1 is grounded, the other end of the resistor R3 is connected with one end of an inductor L1, the other end of the inductor L1 is connected with a first voltage, the negative electrode input end of the operational amplifier U1 is connected with the output end of the operational amplifier U1, and the output end of the operational amplifier U1 is used for outputting a required signal.
3. The optical fiber gain medium protection device of claim 2, wherein: the photoelectric conversion circuit further comprises an operational amplifier U2, the positive input end of the operational amplifier U2 is used for receiving signals output by the operational amplifier U1, the negative input end of the operational amplifier U2 is respectively connected with one end of a resistor R5 and the first fixed end of a potentiometer RW1, the other end of the resistor R5 is grounded, the second fixed end of the potentiometer RW1 and the sliding end of the potentiometer RW1 are connected with the output end of the operational amplifier U2, and the output end of the operational amplifier U2 is used for outputting required signals.
4. A fiber gain medium protection device according to claim 2 or 3, wherein: the photoelectric conversion circuit further comprises a filtering and current limiting circuit, and the filtering and current limiting circuit is arranged at the output end of the operational amplifier U1.
5. The optical fiber gain medium protection device of claim 1, wherein: the comparison circuit comprises an operational amplifier U3, the positive input end of the operational amplifier U3 is connected with one end of a resistor R6, the other end of the resistor R6 is connected with the output end of the photoelectric conversion circuit, the negative input end of the operational amplifier U3 is respectively connected with one end of a capacitor C8 and the sliding end of a potentiometer RW2, the other end of the capacitor C8 is grounded, the first fixed end of the potentiometer RW2 is grounded, the second fixed end of the potentiometer RW2 is connected with a second voltage, the output end of the operational amplifier U3 is connected with one end of a resistor R7, the other end of the resistor R7 is connected with the second voltage, and the output end of the operational amplifier U3 is the output end of the comparison circuit.
6. A laser system, characterized by: comprising a seed light source, an optical splitter, a pump source, a photonic crystal fiber, and an optical fiber gain medium protection device according to any one of claims 1 to 5;
the seed light source is used for outputting seed light;
the optical splitter is used for receiving the seed light and dividing the seed light into two paths, wherein one path of light is transmitted to the photonic crystal fiber through the seed optical coupling system, and the other path of light is transmitted to the fiber gain medium protection device;
the optical fiber gain medium protection device is used for receiving the seed optical signal, carrying out anomaly detection and controlling the working state of the pumping source;
the pump source is used for outputting pump light and is coupled into the photonic crystal fiber through the pump optical coupling system.
7. A method for protecting an optical fiber gain medium of a femtosecond laser, wherein the optical fiber gain medium protection apparatus as set forth in any one of claims 1 to 5 is used, comprising the steps of:
s1) dividing part of input signal light of the photonic crystal fiber according to a set proportion and inputting the part of the input signal light as an input optical signal into a photoelectric conversion circuit;
s2) the photoelectric conversion circuit receives an input optical signal, converts the optical signal into an electric signal and inputs the electric signal to the comparison circuit or/and the sampling circuit respectively;
s3) sampling the analog signal output by the photoelectric conversion circuit in real time by the sampling circuit, transmitting the sampling value to the control module, receiving the sampling value by the control module, comparing the sampling value with a preset alarm range value, and executing the step S4 when the sampling value exceeds the preset alarm range value;
the comparison circuit receives the analog signal output by the photoelectric conversion circuit in real time, compares the analog signal with a preset comparison value, outputs a comparison result to the control module, and executes the step S4 when the control module judges that the comparison result is abnormal;
s4) the control module outputs a control signal to the power supply control circuit to control the power supply control circuit to cut off the power supply and the current of the pumping source.
8. The method for protecting the optical fiber gain medium of the femtosecond laser according to claim 7, wherein: the comparison circuit receives the analog signal output by the photoelectric conversion circuit in real time, compares the analog signal with a preset comparison value, outputs a first level to the control module when the analog signal is larger than the preset comparison value, and outputs a second level to the control module when the analog signal is smaller than the preset comparison value;
when the control module finds that the input level jumps from the first level to the second level, step S4 is performed.
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| CN205565283U (en) * | 2015-12-29 | 2016-09-07 | 中国科学院西安光学精密机械研究所 | Real-time protection device for optical fiber amplifier and laser thereof |
| CN110011175A (en) * | 2019-05-09 | 2019-07-12 | 无锡市德科立光电子技术有限公司 | The small-sized image intensifer of hardware power control |
| CN113300205A (en) * | 2021-05-20 | 2021-08-24 | 上海瀚宇光纤通信技术有限公司 | Fiber laser protection system and device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN205565283U (en) * | 2015-12-29 | 2016-09-07 | 中国科学院西安光学精密机械研究所 | Real-time protection device for optical fiber amplifier and laser thereof |
| CN110011175A (en) * | 2019-05-09 | 2019-07-12 | 无锡市德科立光电子技术有限公司 | The small-sized image intensifer of hardware power control |
| CN113300205A (en) * | 2021-05-20 | 2021-08-24 | 上海瀚宇光纤通信技术有限公司 | Fiber laser protection system and device |
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